Improvement in electrographic printing



.A. W. THOMPSON. Electroplating.

No. 4,012 Patented April 26, I845.

TME mums warms co. momufua, wunmm'ou. n cy UNITED STATES PATENT OFFICE.

A. W. THOMPSON, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN ELECTROGRAPHIC PRINTING.

To all whom it may concern:

Be it known that I, A. W. THOMPSON, of the city of Philadelphia, in the State of Pennsylvania, have invented a new and useful Improvement in the manner of preparing blocks or plates with raised designs for the purpose of giving impressions in the manner of type or block printing and for other purposes; and I do hereby declare that the following is a full and exact description thereof.

My mannerof or process for preparing blocks or plates with raised lines thereon, so as to afi'ord impressions when used for printing typographically or for other purposes, I denominateelectrography,-" and is as follows: I take a piece of glass, metal, wood, or any other suitable substance havinga flat surface, or otherwise soformed as to adapt it to the purpose intended,and upon this I spread evenly alayer of the common etching-ground of engravers, or of a mixture of wax and spermaceti, or of. wax alone, or of spermaceti, or of any other material or composition of matter which will readily admit an etching-pointer other similar instrument to pass through it and leave clean lines without separating or disturbing the portions thereof left between such lines or detach- I then, in general, render such coating white ,on its surface by applying thereto the oxide of bismuth, flake white, or any analogous white material of sufficient fineness. Upon the ground so prepared there may be traced or transferred, in the modes well known to engravers and other artists, the outline and any other portion of the required design. In some cases the artist may not deem such tracing or transfer necessary, but may proceed at once to draw the intended design upon the prepared block with the proper instruments. In either case, pointed tools of various size are to be prepared, so as to be adapted to the formin g of lines of different widths. With these the figure to be formed is to be traced, as with an etching-point, in such manner as to out entirely through the coating down to the surface upon which it is spread, so that the lines may all be of equal depth. When this drawing or cutting of the design is completed those parts thereof which are to be left white in the printing may be so raised as to produce, when reversed, a surface sufliciently sunken for the purpose intended, and this is to be done by adding, while in a suitable state of softness or fluidity, more of the. ground first used or of any other substance or composition which will adhere properly to the first ground. When this has become sufficiently hard and fixed, I give to it a metallic or other surface which is a conductor of the electric fluid, such as gold or silver leaf, plumbago, nitrate of silver, &c. The block or surface so prepared is then placed in a suitable box or vessel for receivin g a deposit of copper or other metal, which is to be precipitated thereon bythe wellknown eleetrotype process, and when the deposit of metal has become sufficiently thick the plate is to be taken from the battery, and the design th us formed in relief is to be mounted in a manner suitable for printing or for otherwise taking impressions thereii-onn Having thus fully described the manner in which I prepare blocks or plates for giving impressions from designs typographically and for other purposes, I will here remark that the said process may be applied to the preparing of tools or instruments for the gilding or the impressing of leather, paper, or other articles which require the design on such tool or instrument to be in relief, the surface upon which the etching or other ground is to be laid having such form given to it as-may be requisite.

What I claim as constituting my invention in the above-described process, and. desire to secure by Letters Patent, is-

The preparing of designs in relief in copper or other suitable metal, for the purpose of printing typographically or for other purposes to which such designs are applicable, in the manner herein set forth of efi'ectin g the samethat is to say, by coating a block or plate of any suitable substance with a ground through which the lines of such design may be cut or traced, as set forth, and giving the same a coating of conducting substance, so that a plate in relief may be obtained therefrom by the electrotype process, as described.

A. W. THOMPSON.

Witnesses:

GEo. W. DONOHUE, ALFRED P. HEssER. 

